{"gene":"SCYL1","run_date":"2026-06-10T07:46:30","timeline":{"discoveries":[{"year":2008,"finding":"SCYL1 binds COPI coat components (coatomer) via a C-terminal RKLD-COO⁻ sequence analogous to the KKXX-COO⁻ ER-retrieval motif, co-immunoprecipitates with βCOP from brain lysates, and localizes to the ERGIC and cis-Golgi in an Arf1-independent manner. RNAi-mediated knockdown of SCYL1 disrupts COPI-mediated retrograde trafficking of the KDEL receptor to the ER without affecting anterograde traffic.","method":"Mass spectrometry-based binding screen, pull-down assays, co-immunoprecipitation, RNAi knockdown with trafficking assay (KDEL receptor retrograde vs. anterograde)","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, pull-down, RNAi functional assay with specific trafficking readout; multiple orthogonal methods in a single rigorous study, independently contextualized by subsequent replication","pmids":["18556652"],"is_preprint":false},{"year":2007,"finding":"Loss-of-function mutation in Scyl1 causes the murine mdf (muscle-deficient) neurodegenerative phenotype comprising cerebellar atrophy, Purkinje cell loss, and optic nerve atrophy. SCYL1 is enriched at CNS synapses and neuromuscular junctions.","method":"Genetic mapping of mdf mouse mutant, histopathology, immunolocalization","journal":"EMBO reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic loss-of-function with defined cellular phenotype and localization; single study but clear causal link via mutation identification","pmids":["17571074"],"is_preprint":false},{"year":2010,"finding":"SCYL1 knockdown increases Golgi surface area and volume and disrupts orderly Golgi ultrastructure (increased cisternal luminal width) without altering Golgi polarity or cisternae number. SCYL1 Golgi localization depends on the golgin p115 network. SCYL1 interacts with the cis-Golgi-associated protein 58K/FTCD.","method":"RNAi knockdown, fluorescence and electron microscopy, co-immunoprecipitation (SCYL1 with FTCD)","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi knockdown with quantitative morphological readout plus Co-IP interaction; single lab, two orthogonal methods","pmids":["20209057"],"is_preprint":false},{"year":2010,"finding":"SCYL1 is a cytoplasmic component of the nuclear tRNA export machinery. It binds tRNA saturably, associates with the nuclear pore complex through interaction with Nup98, co-purifies with exportin-t, exportin-5, RanGTPase, and eEF-1A, interacts directly with exportin-t and RanGTP (but not RanGDP) in vitro, and forms a quaternary complex with exportin-t, tRNA, and RanGTP in vitro. Overexpression of SCYL1 restores export of a nuclear export-defective tRNA mutant.","method":"tRNA export rescue assay in COS-7 cells, saturable tRNA binding assay, co-purification, in vitro binding assays (direct interaction with exportin-t, RanGTP), quaternary complex reconstitution","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution of quaternary complex, direct binding assays with purified proteins, functional rescue assay; single lab with multiple orthogonal methods","pmids":["20505071"],"is_preprint":false},{"year":2012,"finding":"Neural-specific (but not skeletal muscle-specific) deletion of Scyl1 causes progressive motor neuron disease with loss of lower motor neurons, axonal degeneration, and mislocalization/accumulation of TDP-43 and ubiquilin-2 into cytoplasmic inclusions within lower motor neurons, indicating SCYL1 acts cell-autonomously in neurons to maintain TDP-43 proteostasis.","method":"Conditional knockout mice (neural-specific and muscle-specific Cre), histopathology, immunofluorescence for TDP-43 and ubiquilin-2 localization","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean conditional KO with specific cellular phenotype (TDP-43 mislocalization) and cell-autonomy determined by tissue-specific deletion; replicated by subsequent study (PMID:29437892)","pmids":["23175812"],"is_preprint":false},{"year":2014,"finding":"SCYL1 oligomerizes through centrally located HEAT repeats, uses its C-terminal RKXX-COO⁻ motif to bind directly to the appendage domain of γ2-COP (COPG2), and through a distinct site selectively interacts with class II Arfs (notably Arf4), thereby scaffolding class II Arfs to γ2-bearing COPI subcomplexes. Disruption of this scaffolding function causes tubulation of the ERGIC and cis-Golgi.","method":"Co-immunoprecipitation, direct binding assays, domain mapping/mutagenesis, fluorescence microscopy of ERGIC/Golgi morphology upon loss of scaffolding","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP with domain mapping, direct binding assays, functional morphological readout; multiple orthogonal methods in a single study","pmids":["24481816"],"is_preprint":false},{"year":2018,"finding":"Loss of Scyl3 alone has no effect in mice, but combined deletion of Scyl1 and Scyl3 accelerates onset of motor neuron disease compared with Scyl1 deficiency alone. Disease onset correlated with earlier TDP-43 mislocalization in spinal motor neurons, indicating overlapping roles for SCYL1 and SCYL3 in TDP-43 proteostasis and motor neuron viability.","method":"Scyl1/Scyl3 double-knockout mice, behavioral assessment, histopathology, immunofluorescence for TDP-43","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis via double-KO with defined phenotypic readout; single lab","pmids":["29437892"],"is_preprint":false},{"year":2020,"finding":"SCYL1 arginine methylation by PRMT1 at the γ2-COP-binding site is required for the SCYL1–γ2-COP interaction and normal Golgi morphology. PRMT1 co-localizes with SCYL1 in the Golgi fraction. Inhibition of PRMT1 or expression of arginine methylation-defective SCYL1 suppresses axon outgrowth and dendrite complexity via abnormal Golgi morphology.","method":"PRMT1 inhibition, co-localization by fractionation, siRNA knockdown of SCYL1 with rescue by wild-type vs. methylation-deficient mutant SCYL1, neurite outgrowth assays","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — site-specific mutagenesis combined with functional rescue assay and localization; single lab, two orthogonal methods","pmids":["32583741"],"is_preprint":false},{"year":2020,"finding":"In C. elegans, the SCYL1 orthologue SCYL-1 physically interacts with the Slo2 potassium channel (SLO-2) in neurons and increases single-channel open probability (~50% reduction in scyl-1 knockout). Correspondingly, human SCYL1 doubles the open probability of human Slo2.2/Slack in a heterologous expression system, indicating an evolutionarily conserved role as a positive regulator of Slo2 channel activity.","method":"C. elegans genetics (scyl-1 knockout), single-channel patch-clamp electrophysiology, heterologous expression of human SCYL1 with Slo2.2/Slack, physical interaction assay","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro single-channel electrophysiology with KO and heterologous reconstitution, physical interaction demonstrated, replicated across two species","pmids":["32314960"],"is_preprint":false},{"year":2022,"finding":"mTORC1 phosphorylates SCYL1 on Ser754 under growth conditions, maintaining SCYL1 at the Golgi. Upon mTORC1 inhibition, dephosphorylation of Ser754 causes SCYL1 displacement to endosomes, leading to Golgi enlargement, redistribution of early and late endosomes, and increased extracellular vesicle secretion.","method":"mTORC1 inhibitor treatment, phosphomutant SCYL1 (Ser754Ala), live cell imaging and organelle morphology quantification, nanoparticle tracking for extracellular vesicles","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — site-specific phosphomutant combined with pharmacological mTORC1 inhibition, multiple functional readouts (Golgi morphology, endosome redistribution, vesicle secretion); single lab, multiple orthogonal methods","pmids":["35948564"],"is_preprint":false},{"year":2025,"finding":"SCYL1-deficient fibroblasts (CALFAN patient-derived and SCYL1 knockout) accumulate procollagen type I in the ER, display ER distension, and show elevated ER stress and increased cell death, particularly at elevated temperatures mimicking febrile conditions. No procollagen-I trafficking defect was detected, suggesting the primary pathological mechanism is ER stress rather than direct trafficking impairment.","method":"Patient and KO fibroblasts, immunofluorescence/EM for procollagen-I and ER morphology, ER stress markers, cell viability assays at elevated temperature","journal":"Disease models & mechanisms","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — patient-derived and KO cells with multiple orthogonal readouts (ER morphology, stress markers, cell death); single study, single lab","pmids":["41063534"],"is_preprint":false},{"year":2026,"finding":"CTDSPL2 binds SCYL1 (demonstrated by Co-IP) and acts as a phosphatase that suppresses SCYL1 phosphorylation at Ser754. In PTX-resistant breast cancer cells, CTDSPL2 knockdown increases SCYL1 Ser754 phosphorylation; mutating Ser754 to alanine blocks this effect, linking CTDSPL2 to mTORC1-SCYL1 axis and extracellular vesicle secretion.","method":"Co-immunoprecipitation, CTDSPL2 knockdown, SCYL1 Ser754Ala phosphomutant, nanoparticle tracking for extracellular vesicles, in vivo tumorigenesis assay","journal":"Cell cycle","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus site-specific mutant with functional readout; single lab, two orthogonal methods","pmids":["42041204"],"is_preprint":false},{"year":2017,"finding":"SCYL1 does not regulate REST protein levels or turnover: REST steady-state levels and degradation were identical in Scyl1+/+ vs. Scyl1−/− MEFs, CRISPR-Cas9 SCYL1 knockout HEK293T cells, and RNAi-depleted HEK293T or MDA-MB-231 cells. This is a negative result refuting a prior claim that SCYL1 mediates REST degradation.","method":"Scyl1−/− MEFs, CRISPR-Cas9 KO in HEK293T, RNAi in HEK293T and MDA-MB-231; western blot for REST levels and turnover","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — three independent genetic approaches all yield the same negative result; single lab but rigorously replicated within the study","pmids":["28570664"],"is_preprint":false}],"current_model":"SCYL1 is a catalytically inactive pseudokinase that functions as a scaffold at the ERGIC/cis-Golgi, where it binds the γ2-COP appendage domain via its C-terminal RKXX-COO⁻ motif and selectively links class II Arfs (notably Arf4) to γ2-bearing COPI subcomplexes to regulate retrograde membrane trafficking; its Golgi localization and function are controlled by mTORC1-mediated phosphorylation at Ser754 (opposed by the phosphatase CTDSPL2) and by PRMT1-mediated arginine methylation at the γ2-COP binding site, while SCYL1 also participates in cytoplasmic nuclear tRNA export by forming a quaternary complex with exportin-t, tRNA, and RanGTP at the nuclear pore, acts as a positive regulator of Slo2/Slack potassium channel open probability, and loss of SCYL1 causes TDP-43 mislocalization in motor neurons and ER stress-driven cell death in secretory cells, explaining the neurodegenerative and hepatic phenotypes of CALFAN syndrome."},"narrative":{"mechanistic_narrative":"SCYL1 is a multifunctional scaffolding pseudokinase that operates principally at the ERGIC/cis-Golgi interface to organize COPI-mediated retrograde membrane trafficking [PMID:18556652, PMID:24481816]. It binds the coatomer through a C-terminal RKXX-COO⁻ motif that engages the appendage domain of γ2-COP (COPG2), and through a distinct site selectively links class II Arfs (notably Arf4) to γ2-bearing COPI subcomplexes, oligomerizing via central HEAT repeats; disruption of this scaffolding tubulates the ERGIC and cis-Golgi and enlarges the Golgi, while SCYL1 loss impairs retrograde transport of the KDEL receptor without affecting anterograde traffic [PMID:18556652, PMID:24481816, PMID:20209057]. This Golgi-organizing activity is controlled by post-translational regulation: mTORC1 phosphorylates SCYL1 on Ser754 to retain it at the Golgi, and dephosphorylation—promoted by the phosphatase CTDSPL2—displaces SCYL1 to endosomes, enlarging the Golgi and increasing extracellular vesicle secretion [PMID:35948564, PMID:42041204], whereas PRMT1-mediated arginine methylation at the γ2-COP-binding site is required for the SCYL1–γ2-COP interaction, normal Golgi morphology, and neurite outgrowth [PMID:32583741]. Beyond trafficking, SCYL1 acts as a cytoplasmic component of the nuclear tRNA export machinery, binding tRNA and forming a quaternary complex with exportin-t and RanGTP at the nuclear pore [PMID:20505071], and serves as a conserved positive regulator of Slo2/Slack potassium channel open probability [PMID:32314960]. In the nervous system SCYL1 maintains TDP-43 proteostasis cell-autonomously in motor neurons, and its loss causes TDP-43 and ubiquilin-2 cytoplasmic inclusions, progressive motor neuron disease, and cerebellar/Purkinje degeneration [PMID:23175812, PMID:17571074, PMID:29437892]. SCYL1 deficiency also drives ER distension, procollagen-I accumulation, and ER stress-associated cell death in secretory cells, accounting for the neurodegenerative and hepatic features of CALFAN syndrome [PMID:41063534].","teleology":[{"year":2007,"claim":"Establishing a physiological requirement for SCYL1, this work showed that loss of Scyl1 causes a defined neurodegenerative phenotype, placing the gene in CNS maintenance before any molecular mechanism was known.","evidence":"Genetic mapping of the mdf mouse mutant with histopathology and immunolocalization","pmids":["17571074"],"confidence":"Medium","gaps":["No molecular function assigned at this stage","Mechanism linking SCYL1 loss to Purkinje/optic degeneration unresolved"]},{"year":2008,"claim":"Answered what SCYL1 does molecularly by identifying it as a coatomer-binding protein that selectively governs COPI retrograde trafficking, defining its core membrane-traffic role.","evidence":"Mass spectrometry binding screen, reciprocal Co-IP with βCOP, RNAi with KDEL-receptor retrograde vs. anterograde trafficking assay","pmids":["18556652"],"confidence":"High","gaps":["Precise COPI subunit contacts not yet mapped","Role of Arf isoforms unaddressed"]},{"year":2010,"claim":"Two studies refined SCYL1's Golgi role: defining its requirement for Golgi ultrastructure and golgin-dependent localization, and revealing an independent function in nuclear tRNA export.","evidence":"RNAi with EM morphometry and FTCD Co-IP; tRNA export rescue, saturable tRNA binding, co-purification and in vitro quaternary complex reconstitution with exportin-t/RanGTP","pmids":["20209057","20505071"],"confidence":"High","gaps":["How one protein partitions between Golgi and nuclear-pore functions unresolved","Stoichiometry of the tRNA export complex in vivo unknown"]},{"year":2012,"claim":"Determined that SCYL1 acts cell-autonomously in neurons to maintain TDP-43 proteostasis, mechanistically connecting its loss to motor neuron disease.","evidence":"Neural- vs. muscle-specific conditional knockout mice with TDP-43 and ubiquilin-2 immunofluorescence","pmids":["23175812"],"confidence":"High","gaps":["Molecular link between SCYL1 trafficking function and TDP-43 mislocalization not defined"]},{"year":2014,"claim":"Resolved the molecular architecture of SCYL1's scaffolding function, showing it bridges class II Arfs to γ2-COP via discrete domains and controls ERGIC/cis-Golgi membrane shape.","evidence":"Co-IP, domain mapping/mutagenesis, direct binding assays, fluorescence imaging of ERGIC/Golgi tubulation","pmids":["24481816"],"confidence":"High","gaps":["Functional consequence of Arf4 selectivity for specific cargo not established","No structural model of the SCYL1–γ2-COP–Arf assembly"]},{"year":2017,"claim":"Refuted a prior model that SCYL1 mediates REST degradation, removing a putative function from the gene's repertoire.","evidence":"Scyl1−/− MEFs, CRISPR KO HEK293T, and RNAi across cell lines with REST western blots for levels and turnover","pmids":["28570664"],"confidence":"Medium","gaps":["Negative result; does not exclude context-specific regulation"]},{"year":2018,"claim":"Genetic epistasis with Scyl3 showed overlapping roles in TDP-43 proteostasis, indicating functional redundancy within the SCYL family for motor neuron viability.","evidence":"Scyl1/Scyl3 double-knockout mice with behavior, histopathology, and TDP-43 immunofluorescence","pmids":["29437892"],"confidence":"Medium","gaps":["Shared molecular substrate of SCYL1/SCYL3 not identified","Whether redundancy applies to trafficking functions untested"]},{"year":2020,"claim":"Two studies expanded SCYL1's regulation and reach: PRMT1 arginine methylation gates the γ2-COP interaction and neurite outgrowth, and SCYL1 was identified as a conserved positive regulator of Slo2/Slack channel open probability.","evidence":"PRMT1 inhibition, methylation-deficient SCYL1 rescue, neurite assays; C. elegans scyl-1 KO with single-channel patch-clamp and heterologous human SCYL1/Slo2.2 reconstitution","pmids":["32583741","32314960"],"confidence":"High","gaps":["Mechanism by which SCYL1 modulates channel gating unknown","Relationship between channel regulation and trafficking role unclear"]},{"year":2022,"claim":"Identified mTORC1-dependent Ser754 phosphorylation as the switch retaining SCYL1 at the Golgi, linking nutrient signaling to organelle morphology and vesicle secretion.","evidence":"mTORC1 inhibitor treatment, Ser754Ala phosphomutant, organelle imaging and nanoparticle tracking of extracellular vesicles","pmids":["35948564"],"confidence":"High","gaps":["Direct kinase-substrate contact not biochemically resolved","Endosomal function of displaced SCYL1 undefined"]},{"year":2025,"claim":"Defined the cellular basis of CALFAN syndrome pathology, showing SCYL1 loss causes ER stress and cell death rather than a direct procollagen trafficking block.","evidence":"CALFAN patient-derived and KO fibroblasts with procollagen-I/ER imaging, ER stress markers, and viability assays at febrile temperature","pmids":["41063534"],"confidence":"Medium","gaps":["Why ER stress arises despite intact trafficking unresolved","Single-lab study"]},{"year":2026,"claim":"Placed the phosphatase CTDSPL2 opposite mTORC1 on the Ser754 switch, connecting SCYL1 regulation to extracellular vesicle secretion in drug-resistant cancer.","evidence":"Co-IP, CTDSPL2 knockdown, SCYL1 Ser754Ala phosphomutant, nanoparticle tracking and in vivo tumorigenesis","pmids":["42041204"],"confidence":"Medium","gaps":["Direct dephosphorylation of Ser754 by CTDSPL2 not shown biochemically","Generality beyond breast cancer untested"]},{"year":null,"claim":"How SCYL1's distinct molecular activities—COPI scaffolding, tRNA export, and Slo2 channel regulation—are integrated within a single protein, and how each contributes to TDP-43 proteostasis and CALFAN disease, remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model unifying the scaffold/export/channel functions","Mechanistic bridge from trafficking defects to TDP-43 mislocalization undefined","Substrate or cargo selectivity in vivo not mapped"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,5]},{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[3]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[8]}],"localization":[{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[0,2,5,9]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[0,10]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[3]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,5]},{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[3]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[9,11]}],"complexes":["COPI coatomer (γ2-COP/COPG2 subcomplex)","exportin-t–tRNA–RanGTP tRNA export complex"],"partners":["COPG2","ARF4","FTCD","NUP98","XPOT","PRMT1","CTDSPL2","KCNT2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q96KG9","full_name":"N-terminal kinase-like protein","aliases":["Coated vesicle-associated kinase of 90 kDa","SCY1-like protein 1","Telomerase regulation-associated protein","Telomerase transcriptional element-interacting factor","Teratoma-associated tyrosine kinase"],"length_aa":808,"mass_kda":89.6,"function":"Regulates COPI-mediated retrograde protein traffic at the interface between the Golgi apparatus and the endoplasmic reticulum (PubMed:18556652). Involved in the maintenance of the Golgi apparatus morphology (PubMed:26581903) Acts as a transcriptional activator. It binds to three different types of GC-rich DNA binding sites (box-A, -B and -C) in the beta-polymerase promoter region. It also binds to the TERT promoter region","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q96KG9/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/SCYL1","classification":"Common Essential","n_dependent_lines":364,"n_total_lines":1208,"dependency_fraction":0.30132450331125826},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000142186","cell_line_id":"CID001269","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"nucleoplasm","grade":2},{"compartment":"golgi","grade":1}],"interactors":[{"gene":"COPA","stoichiometry":4.0},{"gene":"COPB2","stoichiometry":4.0},{"gene":"COPE","stoichiometry":4.0},{"gene":"CAPZB","stoichiometry":0.2},{"gene":"COPG1","stoichiometry":0.2},{"gene":"COPZ1","stoichiometry":0.2},{"gene":"ATP6V1E1","stoichiometry":0.2},{"gene":"SEC24C","stoichiometry":0.2},{"gene":"COPB1","stoichiometry":0.2},{"gene":"TMED10","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001269","total_profiled":1310},"omim":[{"mim_id":"616719","title":"SPINOCEREBELLAR ATAXIA, AUTOSOMAL RECESSIVE 21; SCAR21","url":"https://www.omim.org/entry/616719"},{"mim_id":"607983","title":"GOLGIN, RAB6-INTERACTING; GORAB","url":"https://www.omim.org/entry/607983"},{"mim_id":"607982","title":"SCY1-LIKE 1; SCYL1","url":"https://www.omim.org/entry/607982"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Cytosol","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/SCYL1"},"hgnc":{"alias_symbol":["HT019","P105","GKLP","NKTL","TAPK","TRAP","TEIF","MGC78454"],"prev_symbol":["NTKL"]},"alphafold":{"accession":"Q96KG9","domains":[{"cath_id":"3.30.200.20","chopping":"15-97","consensus_level":"medium","plddt":90.6582,"start":15,"end":97},{"cath_id":"1.10.510.10","chopping":"99-272","consensus_level":"medium","plddt":92.8667,"start":99,"end":272},{"cath_id":"1.25.10.10","chopping":"463-556_570-586","consensus_level":"medium","plddt":88.8639,"start":463,"end":586}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96KG9","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96KG9-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96KG9-F1-predicted_aligned_error_v6.png","plddt_mean":75.81},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SCYL1","jax_strain_url":"https://www.jax.org/strain/search?query=SCYL1"},"sequence":{"accession":"Q96KG9","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96KG9.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96KG9/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96KG9"}},"corpus_meta":[{"pmid":"18556652","id":"PMC_18556652","title":"Scyl1, mutated in a recessive form of spinocerebellar neurodegeneration, regulates COPI-mediated retrograde traffic.","date":"2008","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/18556652","citation_count":78,"is_preprint":false},{"pmid":"17571074","id":"PMC_17571074","title":"Mutation in the Scyl1 gene encoding amino-terminal kinase-like protein causes a recessive form of spinocerebellar neurodegeneration.","date":"2007","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/17571074","citation_count":59,"is_preprint":false},{"pmid":"20209057","id":"PMC_20209057","title":"Scyl1 regulates Golgi morphology.","date":"2010","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/20209057","citation_count":50,"is_preprint":false},{"pmid":"24481816","id":"PMC_24481816","title":"Scyl1 scaffolds class II Arfs to specific subcomplexes of coatomer through the γ-COP appendage domain.","date":"2014","source":"Journal of cell 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EJHG","url":"https://pubmed.ncbi.nlm.nih.gov/30258122","citation_count":24,"is_preprint":false},{"pmid":"29437892","id":"PMC_29437892","title":"Overlapping Role of SCYL1 and SCYL3 in Maintaining Motor Neuron Viability.","date":"2018","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/29437892","citation_count":22,"is_preprint":false},{"pmid":"38279772","id":"PMC_38279772","title":"Disorders of vesicular trafficking presenting with recurrent acute liver failure: NBAS, RINT1, and SCYL1 deficiency.","date":"2024","source":"Journal of inherited metabolic disease","url":"https://pubmed.ncbi.nlm.nih.gov/38279772","citation_count":20,"is_preprint":false},{"pmid":"32583741","id":"PMC_32583741","title":"SCYL1 arginine methylation by PRMT1 is essential for neurite outgrowth via Golgi morphogenesis.","date":"2020","source":"Molecular biology of the 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carcinoma.","date":"2012","source":"Carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/22570270","citation_count":16,"is_preprint":false},{"pmid":"20598683","id":"PMC_20598683","title":"A newly identified Pirh2 substrate SCYL1-BP1 can bind to MDM2 and accelerate MDM2 self-ubiquitination.","date":"2010","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/20598683","citation_count":15,"is_preprint":false},{"pmid":"19198626","id":"PMC_19198626","title":"Localization of TEIF in the centrosome and its functional association with centrosome amplification in DNA damage, telomere dysfunction and human cancers.","date":"2009","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/19198626","citation_count":12,"is_preprint":false},{"pmid":"15963946","id":"PMC_15963946","title":"Transcriptional upregulation of DNA polymerase beta by TEIF.","date":"2005","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/15963946","citation_count":11,"is_preprint":false},{"pmid":"28570664","id":"PMC_28570664","title":"SCYL1 does not regulate REST expression and turnover.","date":"2017","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/28570664","citation_count":8,"is_preprint":false},{"pmid":"27191590","id":"PMC_27191590","title":"Fission Yeast SCYL1/2 Homologue Ppk32: A Novel Regulator of TOR Signalling That Governs Survival during Brefeldin A Induced Stress to Protein Trafficking.","date":"2016","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/27191590","citation_count":8,"is_preprint":false},{"pmid":"30959346","id":"PMC_30959346","title":"Generation of an induced pluripotent stem cell (iPSC) line, DHMCi005-A, from a patient with CALFAN syndrome due to mutations in SCYL1.","date":"2019","source":"Stem cell research","url":"https://pubmed.ncbi.nlm.nih.gov/30959346","citation_count":8,"is_preprint":false},{"pmid":"25980818","id":"PMC_25980818","title":"SCYL1-BP1 affects cell cycle arrest in human hepatocellular carcinoma cells via Cyclin F and RRM2.","date":"2016","source":"Anti-cancer agents in medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/25980818","citation_count":7,"is_preprint":false},{"pmid":"33442927","id":"PMC_33442927","title":"SCYL1 disease and liver transplantation diagnosed by reanalysis of exome sequencing and deletion/duplication analysis of SCYL1.","date":"2021","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/33442927","citation_count":7,"is_preprint":false},{"pmid":"30717991","id":"PMC_30717991","title":"The factors associated with the early diagnosis of nasal NK/T-cell lymphoma with prominent ocular symptoms and general nasal NKTL.","date":"2019","source":"American journal of otolaryngology","url":"https://pubmed.ncbi.nlm.nih.gov/30717991","citation_count":7,"is_preprint":false},{"pmid":"19958622","id":"PMC_19958622","title":"[Expression of TEIF protein in colorectal tumors and its correlation with centrosome abnormality].","date":"2009","source":"Ai zheng = Aizheng = Chinese journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/19958622","citation_count":7,"is_preprint":false},{"pmid":"32314960","id":"PMC_32314960","title":"Slo2 potassium channel function depends on RNA editing-regulated expression of a SCYL1 protein.","date":"2020","source":"eLife","url":"https://pubmed.ncbi.nlm.nih.gov/32314960","citation_count":6,"is_preprint":false},{"pmid":"36290821","id":"PMC_36290821","title":"Overexpression of SCYL1 Is Associated with Progression of Breast Cancer.","date":"2022","source":"Current oncology (Toronto, Ont.)","url":"https://pubmed.ncbi.nlm.nih.gov/36290821","citation_count":4,"is_preprint":false},{"pmid":"24769208","id":"PMC_24769208","title":"TEIF associated centrosome activity is regulated by EGF/PI3K/Akt signaling.","date":"2014","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/24769208","citation_count":4,"is_preprint":false},{"pmid":"23479292","id":"PMC_23479292","title":"SCY1-like 1 binding protein 1 (SCYL1-bp1) interacts with p53-induced RING H2 protein (Pirh2) after traumatic brain injury in rats.","date":"2013","source":"Journal of molecular histology","url":"https://pubmed.ncbi.nlm.nih.gov/23479292","citation_count":3,"is_preprint":false},{"pmid":"39394539","id":"PMC_39394539","title":"SCYL1-mediated regulation of the mTORC1 signaling pathway inhibits autophagy and promotes gastric cancer metastasis.","date":"2024","source":"Journal of cancer research and clinical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/39394539","citation_count":2,"is_preprint":false},{"pmid":"17374207","id":"PMC_17374207","title":"[Expression of TEIF protein in soft tissue tumors and its significance].","date":"2006","source":"Zhonghua bing li xue za zhi = Chinese journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/17374207","citation_count":2,"is_preprint":false},{"pmid":"25234469","id":"PMC_25234469","title":"Transcriptional profiling and dynamical regulation analysis identify potential kernel target genes of SCYL1-BP1 in HEK293T cells.","date":"2014","source":"Molecules and cells","url":"https://pubmed.ncbi.nlm.nih.gov/25234469","citation_count":2,"is_preprint":false},{"pmid":"41063534","id":"PMC_41063534","title":"SCYL1 deficiency in CALFAN syndrome is associated with ER stress and cell death.","date":"2025","source":"Disease models & mechanisms","url":"https://pubmed.ncbi.nlm.nih.gov/41063534","citation_count":0,"is_preprint":false},{"pmid":"42041204","id":"PMC_42041204","title":"CTDSPL2 facilitates resistance to paclitaxel in breast cancer cells by suppressing SCYL1 phosphorylation.","date":"2026","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/42041204","citation_count":0,"is_preprint":false},{"pmid":"42256251","id":"PMC_42256251","title":"Recurrent Liver Failure due to SCYL1 Deficiency: A Report of 2 Cases and a Review of the Literature.","date":"2026","source":"Journal of clinical and experimental hepatology","url":"https://pubmed.ncbi.nlm.nih.gov/42256251","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":18480,"output_tokens":3848,"usd":0.05658,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11510,"output_tokens":4164,"usd":0.080825,"stage2_stop_reason":"end_turn"},"total_usd":0.137405,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2008,\n      \"finding\": \"SCYL1 binds COPI coat components (coatomer) via a C-terminal RKLD-COO⁻ sequence analogous to the KKXX-COO⁻ ER-retrieval motif, co-immunoprecipitates with βCOP from brain lysates, and localizes to the ERGIC and cis-Golgi in an Arf1-independent manner. RNAi-mediated knockdown of SCYL1 disrupts COPI-mediated retrograde trafficking of the KDEL receptor to the ER without affecting anterograde traffic.\",\n      \"method\": \"Mass spectrometry-based binding screen, pull-down assays, co-immunoprecipitation, RNAi knockdown with trafficking assay (KDEL receptor retrograde vs. anterograde)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, pull-down, RNAi functional assay with specific trafficking readout; multiple orthogonal methods in a single rigorous study, independently contextualized by subsequent replication\",\n      \"pmids\": [\"18556652\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Loss-of-function mutation in Scyl1 causes the murine mdf (muscle-deficient) neurodegenerative phenotype comprising cerebellar atrophy, Purkinje cell loss, and optic nerve atrophy. SCYL1 is enriched at CNS synapses and neuromuscular junctions.\",\n      \"method\": \"Genetic mapping of mdf mouse mutant, histopathology, immunolocalization\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic loss-of-function with defined cellular phenotype and localization; single study but clear causal link via mutation identification\",\n      \"pmids\": [\"17571074\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"SCYL1 knockdown increases Golgi surface area and volume and disrupts orderly Golgi ultrastructure (increased cisternal luminal width) without altering Golgi polarity or cisternae number. SCYL1 Golgi localization depends on the golgin p115 network. SCYL1 interacts with the cis-Golgi-associated protein 58K/FTCD.\",\n      \"method\": \"RNAi knockdown, fluorescence and electron microscopy, co-immunoprecipitation (SCYL1 with FTCD)\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi knockdown with quantitative morphological readout plus Co-IP interaction; single lab, two orthogonal methods\",\n      \"pmids\": [\"20209057\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"SCYL1 is a cytoplasmic component of the nuclear tRNA export machinery. It binds tRNA saturably, associates with the nuclear pore complex through interaction with Nup98, co-purifies with exportin-t, exportin-5, RanGTPase, and eEF-1A, interacts directly with exportin-t and RanGTP (but not RanGDP) in vitro, and forms a quaternary complex with exportin-t, tRNA, and RanGTP in vitro. Overexpression of SCYL1 restores export of a nuclear export-defective tRNA mutant.\",\n      \"method\": \"tRNA export rescue assay in COS-7 cells, saturable tRNA binding assay, co-purification, in vitro binding assays (direct interaction with exportin-t, RanGTP), quaternary complex reconstitution\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution of quaternary complex, direct binding assays with purified proteins, functional rescue assay; single lab with multiple orthogonal methods\",\n      \"pmids\": [\"20505071\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Neural-specific (but not skeletal muscle-specific) deletion of Scyl1 causes progressive motor neuron disease with loss of lower motor neurons, axonal degeneration, and mislocalization/accumulation of TDP-43 and ubiquilin-2 into cytoplasmic inclusions within lower motor neurons, indicating SCYL1 acts cell-autonomously in neurons to maintain TDP-43 proteostasis.\",\n      \"method\": \"Conditional knockout mice (neural-specific and muscle-specific Cre), histopathology, immunofluorescence for TDP-43 and ubiquilin-2 localization\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean conditional KO with specific cellular phenotype (TDP-43 mislocalization) and cell-autonomy determined by tissue-specific deletion; replicated by subsequent study (PMID:29437892)\",\n      \"pmids\": [\"23175812\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"SCYL1 oligomerizes through centrally located HEAT repeats, uses its C-terminal RKXX-COO⁻ motif to bind directly to the appendage domain of γ2-COP (COPG2), and through a distinct site selectively interacts with class II Arfs (notably Arf4), thereby scaffolding class II Arfs to γ2-bearing COPI subcomplexes. Disruption of this scaffolding function causes tubulation of the ERGIC and cis-Golgi.\",\n      \"method\": \"Co-immunoprecipitation, direct binding assays, domain mapping/mutagenesis, fluorescence microscopy of ERGIC/Golgi morphology upon loss of scaffolding\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP with domain mapping, direct binding assays, functional morphological readout; multiple orthogonal methods in a single study\",\n      \"pmids\": [\"24481816\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Loss of Scyl3 alone has no effect in mice, but combined deletion of Scyl1 and Scyl3 accelerates onset of motor neuron disease compared with Scyl1 deficiency alone. Disease onset correlated with earlier TDP-43 mislocalization in spinal motor neurons, indicating overlapping roles for SCYL1 and SCYL3 in TDP-43 proteostasis and motor neuron viability.\",\n      \"method\": \"Scyl1/Scyl3 double-knockout mice, behavioral assessment, histopathology, immunofluorescence for TDP-43\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis via double-KO with defined phenotypic readout; single lab\",\n      \"pmids\": [\"29437892\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SCYL1 arginine methylation by PRMT1 at the γ2-COP-binding site is required for the SCYL1–γ2-COP interaction and normal Golgi morphology. PRMT1 co-localizes with SCYL1 in the Golgi fraction. Inhibition of PRMT1 or expression of arginine methylation-defective SCYL1 suppresses axon outgrowth and dendrite complexity via abnormal Golgi morphology.\",\n      \"method\": \"PRMT1 inhibition, co-localization by fractionation, siRNA knockdown of SCYL1 with rescue by wild-type vs. methylation-deficient mutant SCYL1, neurite outgrowth assays\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — site-specific mutagenesis combined with functional rescue assay and localization; single lab, two orthogonal methods\",\n      \"pmids\": [\"32583741\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In C. elegans, the SCYL1 orthologue SCYL-1 physically interacts with the Slo2 potassium channel (SLO-2) in neurons and increases single-channel open probability (~50% reduction in scyl-1 knockout). Correspondingly, human SCYL1 doubles the open probability of human Slo2.2/Slack in a heterologous expression system, indicating an evolutionarily conserved role as a positive regulator of Slo2 channel activity.\",\n      \"method\": \"C. elegans genetics (scyl-1 knockout), single-channel patch-clamp electrophysiology, heterologous expression of human SCYL1 with Slo2.2/Slack, physical interaction assay\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro single-channel electrophysiology with KO and heterologous reconstitution, physical interaction demonstrated, replicated across two species\",\n      \"pmids\": [\"32314960\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"mTORC1 phosphorylates SCYL1 on Ser754 under growth conditions, maintaining SCYL1 at the Golgi. Upon mTORC1 inhibition, dephosphorylation of Ser754 causes SCYL1 displacement to endosomes, leading to Golgi enlargement, redistribution of early and late endosomes, and increased extracellular vesicle secretion.\",\n      \"method\": \"mTORC1 inhibitor treatment, phosphomutant SCYL1 (Ser754Ala), live cell imaging and organelle morphology quantification, nanoparticle tracking for extracellular vesicles\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — site-specific phosphomutant combined with pharmacological mTORC1 inhibition, multiple functional readouts (Golgi morphology, endosome redistribution, vesicle secretion); single lab, multiple orthogonal methods\",\n      \"pmids\": [\"35948564\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SCYL1-deficient fibroblasts (CALFAN patient-derived and SCYL1 knockout) accumulate procollagen type I in the ER, display ER distension, and show elevated ER stress and increased cell death, particularly at elevated temperatures mimicking febrile conditions. No procollagen-I trafficking defect was detected, suggesting the primary pathological mechanism is ER stress rather than direct trafficking impairment.\",\n      \"method\": \"Patient and KO fibroblasts, immunofluorescence/EM for procollagen-I and ER morphology, ER stress markers, cell viability assays at elevated temperature\",\n      \"journal\": \"Disease models & mechanisms\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — patient-derived and KO cells with multiple orthogonal readouts (ER morphology, stress markers, cell death); single study, single lab\",\n      \"pmids\": [\"41063534\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"CTDSPL2 binds SCYL1 (demonstrated by Co-IP) and acts as a phosphatase that suppresses SCYL1 phosphorylation at Ser754. In PTX-resistant breast cancer cells, CTDSPL2 knockdown increases SCYL1 Ser754 phosphorylation; mutating Ser754 to alanine blocks this effect, linking CTDSPL2 to mTORC1-SCYL1 axis and extracellular vesicle secretion.\",\n      \"method\": \"Co-immunoprecipitation, CTDSPL2 knockdown, SCYL1 Ser754Ala phosphomutant, nanoparticle tracking for extracellular vesicles, in vivo tumorigenesis assay\",\n      \"journal\": \"Cell cycle\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus site-specific mutant with functional readout; single lab, two orthogonal methods\",\n      \"pmids\": [\"42041204\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"SCYL1 does not regulate REST protein levels or turnover: REST steady-state levels and degradation were identical in Scyl1+/+ vs. Scyl1−/− MEFs, CRISPR-Cas9 SCYL1 knockout HEK293T cells, and RNAi-depleted HEK293T or MDA-MB-231 cells. This is a negative result refuting a prior claim that SCYL1 mediates REST degradation.\",\n      \"method\": \"Scyl1−/− MEFs, CRISPR-Cas9 KO in HEK293T, RNAi in HEK293T and MDA-MB-231; western blot for REST levels and turnover\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — three independent genetic approaches all yield the same negative result; single lab but rigorously replicated within the study\",\n      \"pmids\": [\"28570664\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SCYL1 is a catalytically inactive pseudokinase that functions as a scaffold at the ERGIC/cis-Golgi, where it binds the γ2-COP appendage domain via its C-terminal RKXX-COO⁻ motif and selectively links class II Arfs (notably Arf4) to γ2-bearing COPI subcomplexes to regulate retrograde membrane trafficking; its Golgi localization and function are controlled by mTORC1-mediated phosphorylation at Ser754 (opposed by the phosphatase CTDSPL2) and by PRMT1-mediated arginine methylation at the γ2-COP binding site, while SCYL1 also participates in cytoplasmic nuclear tRNA export by forming a quaternary complex with exportin-t, tRNA, and RanGTP at the nuclear pore, acts as a positive regulator of Slo2/Slack potassium channel open probability, and loss of SCYL1 causes TDP-43 mislocalization in motor neurons and ER stress-driven cell death in secretory cells, explaining the neurodegenerative and hepatic phenotypes of CALFAN syndrome.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SCYL1 is a multifunctional scaffolding pseudokinase that operates principally at the ERGIC/cis-Golgi interface to organize COPI-mediated retrograde membrane trafficking [#0, #5]. It binds the coatomer through a C-terminal RKXX-COO\\u207b motif that engages the appendage domain of \\u03b32-COP (COPG2), and through a distinct site selectively links class II Arfs (notably Arf4) to \\u03b32-bearing COPI subcomplexes, oligomerizing via central HEAT repeats; disruption of this scaffolding tubulates the ERGIC and cis-Golgi and enlarges the Golgi, while SCYL1 loss impairs retrograde transport of the KDEL receptor without affecting anterograde traffic [#0, #5, #2]. This Golgi-organizing activity is controlled by post-translational regulation: mTORC1 phosphorylates SCYL1 on Ser754 to retain it at the Golgi, and dephosphorylation\\u2014promoted by the phosphatase CTDSPL2\\u2014displaces SCYL1 to endosomes, enlarging the Golgi and increasing extracellular vesicle secretion [#9, #11], whereas PRMT1-mediated arginine methylation at the \\u03b32-COP-binding site is required for the SCYL1\\u2013\\u03b32-COP interaction, normal Golgi morphology, and neurite outgrowth [#7]. Beyond trafficking, SCYL1 acts as a cytoplasmic component of the nuclear tRNA export machinery, binding tRNA and forming a quaternary complex with exportin-t and RanGTP at the nuclear pore [#3], and serves as a conserved positive regulator of Slo2/Slack potassium channel open probability [#8]. In the nervous system SCYL1 maintains TDP-43 proteostasis cell-autonomously in motor neurons, and its loss causes TDP-43 and ubiquilin-2 cytoplasmic inclusions, progressive motor neuron disease, and cerebellar/Purkinje degeneration [#4, #1, #6]. SCYL1 deficiency also drives ER distension, procollagen-I accumulation, and ER stress-associated cell death in secretory cells, accounting for the neurodegenerative and hepatic features of CALFAN syndrome [#10].\",\n  \"teleology\": [\n    {\n      \"year\": 2007,\n      \"claim\": \"Establishing a physiological requirement for SCYL1, this work showed that loss of Scyl1 causes a defined neurodegenerative phenotype, placing the gene in CNS maintenance before any molecular mechanism was known.\",\n      \"evidence\": \"Genetic mapping of the mdf mouse mutant with histopathology and immunolocalization\",\n      \"pmids\": [\"17571074\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No molecular function assigned at this stage\", \"Mechanism linking SCYL1 loss to Purkinje/optic degeneration unresolved\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Answered what SCYL1 does molecularly by identifying it as a coatomer-binding protein that selectively governs COPI retrograde trafficking, defining its core membrane-traffic role.\",\n      \"evidence\": \"Mass spectrometry binding screen, reciprocal Co-IP with \\u03b2COP, RNAi with KDEL-receptor retrograde vs. anterograde trafficking assay\",\n      \"pmids\": [\"18556652\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise COPI subunit contacts not yet mapped\", \"Role of Arf isoforms unaddressed\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Two studies refined SCYL1's Golgi role: defining its requirement for Golgi ultrastructure and golgin-dependent localization, and revealing an independent function in nuclear tRNA export.\",\n      \"evidence\": \"RNAi with EM morphometry and FTCD Co-IP; tRNA export rescue, saturable tRNA binding, co-purification and in vitro quaternary complex reconstitution with exportin-t/RanGTP\",\n      \"pmids\": [\"20209057\", \"20505071\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How one protein partitions between Golgi and nuclear-pore functions unresolved\", \"Stoichiometry of the tRNA export complex in vivo unknown\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Determined that SCYL1 acts cell-autonomously in neurons to maintain TDP-43 proteostasis, mechanistically connecting its loss to motor neuron disease.\",\n      \"evidence\": \"Neural- vs. muscle-specific conditional knockout mice with TDP-43 and ubiquilin-2 immunofluorescence\",\n      \"pmids\": [\"23175812\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular link between SCYL1 trafficking function and TDP-43 mislocalization not defined\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Resolved the molecular architecture of SCYL1's scaffolding function, showing it bridges class II Arfs to \\u03b32-COP via discrete domains and controls ERGIC/cis-Golgi membrane shape.\",\n      \"evidence\": \"Co-IP, domain mapping/mutagenesis, direct binding assays, fluorescence imaging of ERGIC/Golgi tubulation\",\n      \"pmids\": [\"24481816\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of Arf4 selectivity for specific cargo not established\", \"No structural model of the SCYL1\\u2013\\u03b32-COP\\u2013Arf assembly\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Refuted a prior model that SCYL1 mediates REST degradation, removing a putative function from the gene's repertoire.\",\n      \"evidence\": \"Scyl1\\u2212/\\u2212 MEFs, CRISPR KO HEK293T, and RNAi across cell lines with REST western blots for levels and turnover\",\n      \"pmids\": [\"28570664\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Negative result; does not exclude context-specific regulation\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Genetic epistasis with Scyl3 showed overlapping roles in TDP-43 proteostasis, indicating functional redundancy within the SCYL family for motor neuron viability.\",\n      \"evidence\": \"Scyl1/Scyl3 double-knockout mice with behavior, histopathology, and TDP-43 immunofluorescence\",\n      \"pmids\": [\"29437892\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Shared molecular substrate of SCYL1/SCYL3 not identified\", \"Whether redundancy applies to trafficking functions untested\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Two studies expanded SCYL1's regulation and reach: PRMT1 arginine methylation gates the \\u03b32-COP interaction and neurite outgrowth, and SCYL1 was identified as a conserved positive regulator of Slo2/Slack channel open probability.\",\n      \"evidence\": \"PRMT1 inhibition, methylation-deficient SCYL1 rescue, neurite assays; C. elegans scyl-1 KO with single-channel patch-clamp and heterologous human SCYL1/Slo2.2 reconstitution\",\n      \"pmids\": [\"32583741\", \"32314960\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which SCYL1 modulates channel gating unknown\", \"Relationship between channel regulation and trafficking role unclear\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified mTORC1-dependent Ser754 phosphorylation as the switch retaining SCYL1 at the Golgi, linking nutrient signaling to organelle morphology and vesicle secretion.\",\n      \"evidence\": \"mTORC1 inhibitor treatment, Ser754Ala phosphomutant, organelle imaging and nanoparticle tracking of extracellular vesicles\",\n      \"pmids\": [\"35948564\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct kinase-substrate contact not biochemically resolved\", \"Endosomal function of displaced SCYL1 undefined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Defined the cellular basis of CALFAN syndrome pathology, showing SCYL1 loss causes ER stress and cell death rather than a direct procollagen trafficking block.\",\n      \"evidence\": \"CALFAN patient-derived and KO fibroblasts with procollagen-I/ER imaging, ER stress markers, and viability assays at febrile temperature\",\n      \"pmids\": [\"41063534\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Why ER stress arises despite intact trafficking unresolved\", \"Single-lab study\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Placed the phosphatase CTDSPL2 opposite mTORC1 on the Ser754 switch, connecting SCYL1 regulation to extracellular vesicle secretion in drug-resistant cancer.\",\n      \"evidence\": \"Co-IP, CTDSPL2 knockdown, SCYL1 Ser754Ala phosphomutant, nanoparticle tracking and in vivo tumorigenesis\",\n      \"pmids\": [\"42041204\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct dephosphorylation of Ser754 by CTDSPL2 not shown biochemically\", \"Generality beyond breast cancer untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How SCYL1's distinct molecular activities\\u2014COPI scaffolding, tRNA export, and Slo2 channel regulation\\u2014are integrated within a single protein, and how each contributes to TDP-43 proteostasis and CALFAN disease, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model unifying the scaffold/export/channel functions\", \"Mechanistic bridge from trafficking defects to TDP-43 mislocalization undefined\", \"Substrate or cargo selectivity in vivo not mapped\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 5]},\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [0, 2, 5, 9]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [0, 10]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0005643\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 5]},\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [9, 11]}\n    ],\n    \"complexes\": [\n      \"COPI coatomer (\\u03b32-COP/COPG2 subcomplex)\",\n      \"exportin-t\\u2013tRNA\\u2013RanGTP tRNA export complex\"\n    ],\n    \"partners\": [\n      \"COPG2\",\n      \"Arf4\",\n      \"FTCD\",\n      \"Nup98\",\n      \"XPOT\",\n      \"PRMT1\",\n      \"CTDSPL2\",\n      \"KCNT2\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}